Chip scale package

Abstract

The present invention discloses a chip scale package. According to this invention, a lead frame 130 is bonded with an adhesive 140 to a bottom face of a semiconductor chip 110 . An inner lead 131 of the lead frame 130 is connected to a pad 111 of the semiconductor chip with a metal wire 120 , and thickness of the inner lead 131 is equal to an original thickness of the lead frame 130 . An outer lead 132 of the lead frame 130 is formed by partially etching a bottom face of the lead frame 130 . The entire resultant is encapsulated with a molding compound 100 such that the outer lead 132 is exposed therefrom, especially there is formed a downward protruding portion 101 at the molding compound 100 in the lower inner lead portion 131 . This protruding portion raises the margin controlling the bonding height during the wire-bonding process such that the metal wire 120 is not exposed from the molding compound 100 . Furthermore, the outer leads 134 at both sides where no solder balls are mounted on, are exposed from the molding compound 100 . The outer leads 132 at both sides being exposed from the molding compound 100 act for dissipating outwardly heat that is transmitted from the semiconductor chip 110 to the lead frame 130 . A solder ball 150 is mounted at the inside of the outer lead 132 exposed from the molding compound 100.

What is claimed is:  
     
       1. A chip scale package comprising: 
       a semiconductor chip disposed such that its bonding pad is disposed downward;  
       a lead frame attached to a bottom face of the semiconductor chip and comprising inner and outer leads;  
       a metal wire electrically connecting the inner lead of the lead frame and the bonding pad of the semiconductor chip;  
       a molding compound for encapsulating an entire resultant such that the outer lead is exposed therefrom, and wherein a protruding portion for preventing the metal wire from exposing is formed below the inner lead; and  
       a solder ball mounted on the outer lead exposed from the molding compound,  
       wherein the outer lead of the lead frame is formed by partially etching the bottom face of the lead frame and then thickness of the inner lead becomes equal to an original thickness of the lead frame.  
     
     
       2. The chip scale package of claim  1 , wherein the protruding portion of the molding compound is also formed at both sides of the solder ball. 
     
     
       3. The chip scale package of claim  1 , wherein a surface of the semiconductor chip is exposed from the molding compound and a heat sink is attached to the exposed surface of the semiconductor chip. 
     
     
       4. The chip scale package of claim  1 , wherein a recess having a shape corresponding to the shape of the solder ball is formed on a surface of the outer lead. 
     
     
       5. The chip scale package of claim  4 , wherein a metal layer is deposited on a surface of the recess. 
     
     
       6. The chip scale package of claim  1 , wherein a metal ring is plated on a surface of the outer lead. 
     
     
       7. The chip scale package of claim  1 , wherein a metal layer is plated on a surface of the outer lead. 
     
     
       8. The chip scale package as in any of claims  5  to  7 , wherein the metal layer or the metal ring is an alloy made of one or two materials selected from a group consisting of Cu, Au, Ag, Ni, Pd, Pb, Sn, Co, Ti and Cr. 
     
     
       9. The chip scale package of claim  1 , wherein both sides portions of the lead frame which are not etched, are exposed from the molding compound so as to dissipate outwardly heat that is transmitted from the semiconductor chip to the lead frame.